Noticed 2 mths ago my front l+r speakers wernt working properly- sound from both is barely audible+sounds tinny(with all inputs incl dvd, tv etc). Mission 73 speakers btw. Connections are fine- the speakers work properly on other amps so im presuming theres a fault in the 5200. Centre+2 surrounds work fine. Anything else i should check before trying to get it repaired? Thanks!